The motion of planar hinge-lever mechanisms with flexible and elastic links in a closed pre-stressed contour is considered. Modeling of the mechanism motion is carried out on the basis of their kinetic-elastodynamic analysis, which takes into account the inertial relationship between the large-scale motion of mechanisms as a rigid body and nonlinear vibrations of the links as a result of their elastic deformation. This work pays attention to both longitudinal and lateral vibrations of elastic links. The equations of motion of the mechanisms are obtained by the use of Novozhilov’s nonlinear theory of elasticity, according to which the link deformations are assumed to be finite. Based on Biot’s theory of incremental deformations, the field of initial stresses in flexible elements is taken into account due to their preliminary tension, which determines the geometric nonlinearity of dynamic models. As an example, the dynamics of a planar five-link hinge-lever mechanism with closed pre-stressed contour is studied. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Hydrotechnical structures, being vital infrastructural objects, at the same time represent a great danger for human activity and the environment. The article discusses the results of geophysical studies of an earth dam in Kazakhstan. Despite its key role in agricultural water supply, the loam dam has not previously been subjected to a thorough geophysical evaluation. The study combines seismic refraction tomography using the correlation method of refracted waves with self-potential measurements to non-invasively detect internal heterogeneities and potential seepage pathways. Over one kilometre of seismic profiling has been performed with both P- and S-wave registrations by using standard geophones and pulse sources, allowing imaging to depths of up to 40 meters. Data processing included noise reduction, first arrival sampling, and velocity modelling with vertical gradients. The results show significant lithological and structural variability in the dam body. Subsidence anomalies with increasing permeable loams and low velocity zones have been identified, and soil loosening has been detected, indicating a possible seepage site. The comparison of seismic data and self-potential measurements has showed the highest correlation near the dam crest, with partial overlap elsewhere due to soil heterogeneity, metal structures, moisture changes, and complex topography. The combined interpretation has allowed identifying the main seepage zones in the dam body. The results of the study confirm the effectiveness of combining the correlation method of refracted waves and the self-potential method for detailed diagnostics of earth dams. The integrated approach allows for depth-resolved characterization and the development of a seepage regime model that identifies critical risk zones. Further detailed permeability testing, real-time seepage monitoring, and regular geophysical and hydrogeological surveys are recommended, especially near residential areas. The results of the surveys provide a solid foundation for engineering measures to enhance dam safety and mitigate the risk of failure. As part of the Geographic Information System platform, the data obtained are useful for monitoring the condition of dams, assessing their risks and impact on the environment, and for effective water resource management.

Abstract. Relevance. This study presents a machine learning (ML) approach for petrophysical core classification, applied to data from the southeastern margin of the Precaspian Depression - a geologically complex region characterized by heterogeneous reservoirs and diverse lithofacies. The Random Forest (RF) algorithm was chosen as the primary method due to its proven efficiency in handling nonlinear relationships and high-dimensional datasets, making it particularly suitable for complex geological environments. Objective. A Python based workflow integrating Scikit-learn, Pandas, and Streamlit was developed to support the complete petrophysical analytical cycle — from data preprocessing to interactive visualization and interpretation. Methods. The RF model achieved 89% accuracy and an F1-score of 0.90 in lithotype classification (sandstones and siltstones). Porosity and permeability emerged as the most influential features, with the application of a logarithmic permeability scale significantly enhancing interpretability in low-permeability zones. Feature importance was rigorously quantified using the Gini index, enabling effective dataset optimization and 8 ISSN 2224-5278 2.2026 dimensionality reduction. Results and conclusions. The model exhibited strong generalization capabilities, with over 90% test accuracy, and demonstrated robust resistance to overfitting, ensuring reliable performance on unseen data. The interactive web application further enhances usability by offering tools for hyperparameter tuning, feature importance analysis, and dynamic data visualization, supporting rapid and informed decision-making by petrophysicists. In conclusion, the proposed ML framework offers a practical, scalable, and adaptable solution that significantly improves the speed, accuracy, and reliability of lithotype classification, making it a valuable tool for modern petrophysical workflows in geologically complex and heterogeneous reservoir settings.

This work presents a generalization and analysis of the physical properties of rocks and ores from the Zhezkazgan ore district. Studies were carried out to identify general patterns in variations in the magnetic, density, velocity, and electrical parameters of the rocks that make up the geological section of the region. Based on the physical parameter measurements of the rock samples and drill cores collected in large quantities evenly throughout the region, a spatial analysis and quantitative assessment were conducted for the magnetic susceptibility, density, specific electrical resistivity, polarizability, and seismic velocity of the rocks. These properties were systematized at the level of formations, individual suites, and lithological heterogeneities. Correlations between the physical properties of the rocks, their composition, and the conditions of their formation were established. This study demonstrated the potential of using petrophysical characteristics in tectonic studies, geological mapping, and the identification of the exploration and ore-controlling factors in copper mineralization. It was found that the deposits of the productive horizons of the Zhezkazgan and Taskuduk suites are characterized by consistent physical parameters across the entire area, due to their relative homogeneity in lithological, structural–textural, and other features. The physical parameters of the rocks are influenced by several factors associated with mineralization processes, including changes in the total porosity, structure, and texture of the host rocks, alteration of the original mineral composition of the ores, fragmentation, fracturing, fissuring, and others. The obtained results significantly improve the reliability of geologically interpreting geophysical anomalies, especially in areas covered by loose sediments and where productive horizons are deeply buried. The detailed petrophysical analysis of the region has made it possible to provide recommendations for selecting an optimal set of geophysical methods for further successful work at the prospecting-evaluation and exploration stages in the Zhezkazgan ore district. Keywords: physical properties; systematization; variation curves; statistical processing; patterns; Zhezkazgan; stratiform deposits; productive horizon

The study aimed to investigate the impact of plasticizers on the properties of metal-ceramic hard alloys and develop recommendations for optimizing their composition, concentration, and production process parameters. WC8 alloy powder containing 8% cobalt binder and varying tungsten carbide grain sizes (2.5–8 μm) was used. Plasticizers tested included paraffin and polyethylene glycol (PEG) in concentrations of 1–3%. Powder mixtures were pressed under high pressure and subjected to vacuum-compression sintering. Mechanical properties such as bending strength, hardness, and density were analyzed using standard measurement techniques. Plasticizers improved the flowability of powder mixtures and the quality of pressing. Paraffin at concentrations of 1–2% provided the best results, achieving a bending strength of 2030 MPa, a density of 14.8 g/cm³, and a hardness of 88 HRA. PEG showed lower performance due to increased porosity, especially at concentrations of 3%. Reducing tungsten carbide grain size to 2.5 μm further enhanced the mechanical properties of the alloys. Optimal plasticizer concentrations for sintering hard alloys under vacuum-compression conditions were established for the first time. It was determined that paraffin is more effective in forming a homogeneous material structure compared to PEG. The results can be applied in the production of hard alloys for various industries, including mechanical engineering, metallurgy, aerospace, and defense, ensuring improved product quality and reliability.

Purpose. Purpose is to generalize and analyze the currently accumulated geological and physical as well as field data to study productive strata of Prorva group of oil-and-gas occurrence of the Southern deposits of the Caspian Depression in Kazakhstan. Methodology. Deep Triassic rock systems were studied thoroughly relying upon the explained new data by seismic data together with logging and field information using current processing and interpretative systems according to the newly drilled deep wells within the unexplored northwest part of the structure. Findings. The specified geological model of the field has been obtained. Twenty-one estimation targets have been singled out in the Jurassic-Trias structures; three new oil-and-gas-bearing formations have been identified as part of the Lower Cretaceous share of a productive stratum within the Valanginian level. According to geophysical analysis, Western Prorva and S. Nurzhanov deposits are the unified system with the oil-water contact level. Originality. Selection of the recommended location of the new wells is based upon specificity of the innovative scientific and technical approaches while studying regularities of facies substitution of reservoir rocks with enclosing systems of each productive stratum; and studying permeability and porosity of the reservoir rocks as well as fluids saturating them.

A geological and geophysical database of hydrocarbon fields in the Kazakhstan part of the Caspian depression wasbuilt, enabling the efficient geological forecasts and assessment/re-assessment of field reserves. The database has the capacity to reuse and replenish the stored information, allowing the oil and gas companies, engaged in modelling, to effectively address issues of complex interpretation of geological and geophysical data for prospecting, exploration and evaluation, complex geological structure of oil and gas fields. The WEB-based Oil&Gas Resources Database Management System (OGR. Version 1.0) was developed, the pilot loading of initial information on 60 oil and gas fields into the database was carried out, and a basis for using this information in specialized geoinformation systems for building hydrocarbon reservoir models on complex geological and geophysical data was developed. This will enable subsoil users to apply information resources accumulated over many years more quickly and efficiently to prepare digital databases of geological and geophysical data needed to study and monitor the state of the subsoil geological structure, assess hydrocarbon reserves and conditions of their location in the subsoil.

Comprehensive interpretation of geophysical data for studies of the Earth crust deep horizons in the Caspian oil and gas bearing region is based on analysis of regional seismic section wave fields as per reference geotravers and gravity anomalies’ interpretation results received by posing direct and inverse problems with use of specialized geoinformation systems. Gravity exploration data in the form of consolidated medium- and small-scale maps and the observed travel time graphs of DSS and Reflection Wave/DSS refraction waves taken in separate regional profiles serve as the factual basis for construction of deep geological-geophysical sections. Physical models of density and structural-velocity proved to be effective and allowed identifying vertical and lateral heterogeneities in the crust and upper mantle structure. The models for upper horizons of the Earth crust are most reliable, as they are provided with a large amount of factual material, including geological data. Structural-velocity sections built on regional seismic profiles revealed heterogeneous structure of the North-Caspian region’s lithosphere. Negative and positive velocity anomalies characterize the lower horizon blocks of the Earth crust and the upper mantle of different material composition and structure. The gravity models of deep structures and density distribution in the Earth crust allowed to reveal the vertical and sub-vertical boundaries of deep blocks, to predict the material composition of deep structures and to determine the peculiarities of their formation and tectonic development. Given the poorly explored territory and incomplete geophysical information, the proposed method of the complex interpretation of seismic gravimetric data enables to construct reliable density and velocity models of complex geological situation. The obtained models of the region’s deep structure can be effectively used both for reconstruction of Paleozoic geodynamic conditions and identification of the modern structural features of the Earth crust and upper mantle.

В данной работе поддержание необходимой плотности бурового раствора с использованием утяжелителей, таких как сульфат бария (BaSO4), рассматривается как ключевой фактор обеспечения устойчивости ствола скважины и предотвращения осложнений при бурении. Однако внедрение барита в состав бурового раствора может вызывать загрязнение продуктивных пластов, снижая их проницаемость и продуктивность. Проникновение твердых частиц барита в поровое пространство приводит к закупорке пор и фильтрационных каналов, что зачастую становится необратимым без применения специализированных методов очистки. Для снижения риска загрязнения необходимо оптимизировать состав бурового раствора и контролировать параметры бурения. Применение ингибиторов кристаллизации, стабилизаторов и полимерных добавок способствует снижению оседаемости барита и уменьшает его адгезию к стенкам пор. Это позволяет существенно снизить вероятность повреждения продуктивных интервалов. При уже произошедшем загрязнении используются восстановительные технологии. Механическая очистка, включая промывку скважины под давлением, может быть эффективной при поверхностном засорении, однако ограниченно действенна при глубоком проникновении частиц. Более перспективным направлением является использование хелатирующих агентов, способных связывать ионы бария и разрушать баритовые отложения. Эффективность таких реагентов зависит от физических и химических характеристик коллектора. Альтернативой выступают специализированные растворители, селективно растворяющие барит в поровом пространстве. Их применение требует инженерного обоснования и лабораторной верификации.Комплексный подход, включающий корректировку состава раствора, контроль технологических параметров и своевременное применение химических реагентов, способствует сохранению продуктивности пластов и снижению эксплуатационных затрат при бурении скважин.

Complex dynamic systems are characterized by the presence of memory effects and a multi-level hierarchy of relaxation times at various stages of transport processes. Therefore, reliable models of transport phenomena in such systems necessarily include a nonlocality factor due to the aftereffects of disturbances at different time stages of the process. At the same time, control parameters in models describing such dynamic systems can also change at different rates over different time intervals under the influence of external influences and relaxation processes that alter the system's structure. This factor is not always taken into account when constructing a process model. In this paper, a new heuristic model for accounting the impact of disturbances on the model structure and the appropriate control equation for describing the memory effects and the changes in the system's dynamic characteristics have been submitted. The novelty of the approach lies in the new concept for building the model, according to which the manifestation of after-effects can be caused by the memory effects formed, in turns, as a result of a change in the depth of potential wells corresponding to the stationary states of the system during the model process. Such an approach provides mathematical tools for studying bifurcation phenomena in a dynamic system described by a two-parameter model. The details of the new concept and the scheme for deriving the control equation are given. This article is theoretical in nature; the concept is based on general physical considerations. The results of conducted researches and the novel model will nevertheless can find application in engineering practice in the design of various technological processes. © 2026, World Scientific and Engineering Academy and Society. All rights reserved.